Walking Desks: Use a 3% Incline

When at a walking desk, you're walking up to 8 hours a day. Much more than typical fitness regimes, so requires as much ergonomics as possible. 3% incline is the ideal for knee health, and offers other benefits too (better stability, machine longevity, calorie burning).

Incline is a spec in our comparison table: sort or filter every walking pad we track by incline, alongside price, motor and warranty.

Open the full comparison table →

You'll use an under-desk treadmill / walking pad any amount of an 8-hour work day, and it's possible you'll do the full 8 (I usually do). You'll walk somewhere between 1-3 miles per hour; and by week's end, you've put in more mileage than any sane exercise regime (up to 960 miles). So you really need to get the ergonomics right.

Ergonomics

Sports medicine found that 3% is the optimal incline for walking and running (1, 2). The very slight upward climb reduces the distance to impact (thus reducing impact), reduces hyper-extension, and stabilizes the right muscles around the knees. This makes choosing a treadmill easy, since not all offer incline. If yours lacks incline, see the workaround below.

Some worry about lower back strain as a trade-off, but I've never experienced lower back pain (flat or incline). Your back and posture are already improved by walking over sitting, so any concern here is negligible compared to knee health.

Calories and Stability

A 3% incline adds 20-30% more calorie expenditure for the same speed. This means you can set the speed to 20% less than you'd normally walk for the same benefits, meaning you're reclaiming stability at the desk (mouse and keyboard precision). Or you can walk at the same speed as before and lose more weight (I do the latter).

Treadmill Longevity

Two things: (1) motor life; (2) walking pad impact. (1) The treadmill's motor expenditure and wear is based on speed alone. So if you reduce speed by 20% for the same human effort (above), you'll reduce motor load by 20%. (2) The incline reduces the distance to impact, meaning there's less of an impact on the walking pad when foot touches down. This improves health on knees, and improves health on the walking pad of the treadmill.

Buying a Treadmill for Bad Knees

If knees are the reason you're shopping, the spec that decides it is whether the machine inclines at all, and most listings bury that well below the horsepower. Of the 108 walking pads in our comparison table, 55 publish an incline above zero, 38 are confirmed flat, and 15 haven't been confirmed either way. Incline is closer to a coin flip than a standard feature.

Max incline is a ceiling, not a target. Every one of those 55 reaches at least 3%, so the number this whole page is about is not a premium tier: the cheapest pad that inclines hits it as surely as the steepest. A 15% ceiling buys headroom you shouldn't spend: two months living at 14% brought my knee pain right back (below).

What matters is whether you can park it at 3% and leave it there. Of the 55, 26 adjust under power, 22 adjust by hand, 6 are locked at one factory angle, and 1 doesn't say. Check the fixed group by model rather than by category, because a fixed grade only helps if it lands near 3%: two of the six sit at exactly 3% and two more at 5%, while the other two lock in at 8% and 13.5%.

A flat machine isn't a dealbreaker either. The workaround below gets one to roughly 3% with a second mat, and the shock absorption, mat and shoes further down do the rest.

No Incline? Here's a Workaround

Buy a second treadmill mat (a Hapbear Mat works great). Fold it fully and place it under the front feet of your walking pad. This raises the front roughly 3% - enough to get the knee-health benefit described above. The folded mat also doubles as extra shock absorption under the hardest-impact zone. One mat goes on the floor as usual; the second one lives under the front feet.

Extra Knee-Savers

My budget & premium recommends also provide mechanized shock-absorption. I also recommend a treadmill mat, primarily to protect your floors, but doubling as added shock absorption. And of course, a good pair of walking shoes. With these four powers combined - 3% incline, treadmill shock absorption, a treadmill mat, and good shoes - you'll protect your knees significantly. All product recommendations here.

Anecdotal Evidence

I trust the sports medicine expert claims, but I've also experimented with this over 4.5 years. I have bad knees myself. My first treadmills (2 years) were flat. I have knee pain, and it worsened noticeably during that time, thus sparking my research. I switched to 3% for the next 2 years and my knee pain went to 0. My newest treadmill goes to 14%, and I got greedy with the extra caloric burn for 2 months. The pain came right back. So I returned to 3%, and bingo within weeks. So there is a "too much", though flat is worse. My knees tell me everything I need to know and fast.

Now that you know this, take the same knowledge to the gym any time you run on a standard treadmill. 3% should be your fixed incline, no more no less.